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Scott Brown will make another appearance in New Hampshire Thursday, visiting with potential voters in Londonderry. It's just the latest event on his Will He-Won't He Run for U.S. Senate tour in the Granite State. So will he?

Brown will visit the Harold Square restaurant tonight according to the eatery, which sounds like a stop on the campaign trail. But, in an e-mail to ABC News, Brown would only say, "Nothing has changed. I'm all set. Thanks for checking," signing it with an "SB," and then following up with a YouTube video of his daughter, recording artist and former American Idol contestant Ayla Brown singing "O Holy Night."

Brown may be coy, but he has steadily been making moves in the direction of challenging current Democratic senator Jeanne Shaheen - despite the fact that he's a former senator from neighboring Massachusetts. He owns a home in Rye, N.H.,and put his home in the Bay State up for sale in September.

He's been popping up all over the state in the past few months and on Dec. 19 will headline the New Hampshire Republican State Committee's holiday luncheon. And just this week he penned an op-ed on FoxNews.com focusing on Obamacare's effects in New Hampshire, appearing to take a shot at Shaheen.

Former aides, people familiar with his thinking, and those in the know in New Hampshire all say no one really knows the answer, aside from Brown, and that he's still making up his mind.

One former aide of Brown's put his chances at 75-25.

A Republican strategist familiar with his thinking put the odds at 50-50.

"In September, I would have said there was a 20 percent chance, now it is 50 percent or higher, but it's still very tentative," the strategist told ABC News, adding it is "by no means a done deal. He has a good career in the private sector, I think he enjoys his life now, but he is inherently a competitive person and sees the opportunity and thinks he can win."

The strategist, who like others in this piece did not want to be named discussing Brown's thinking, said Brown is "going to watch and see what Jeanne Shaheen's numbers look like after the holidays and then make a decision." But, he added, "I wouldn't expect a January announcement."

The filing deadline in New Hampshire is late - June - but it's likely Brown won't wait that long because Republicans say his indecision is keeping well known and more credible candidates on the sidelines. Just this week former Sen. Bob Smith got into the race, but his two previous Senate runs in Florida as well as switching party affiliations is likely to be problematic for him. Conservative activist Karen Testerman and former state Sen. Jim Reubens have already jumped declared their candidacies.

Brown may not rile up the most conservative voters in the state. He has expressed support for a federal assault weapons ban, and second amendment issues are important in New Hampshire. But Republicans in the state say because of how well known Brown is, they would easily coalesce around him.

Although he would get cries of "carpetbagger" from Democrats, New Hampshire and Massachusetts share a media market so he is well known in the state. Those around him also say he's more likely to jump in now that Obamacare has become a clear issue for any Democrat running in 2014. It's an issue he's familiar running on. When he did win in 2010 to fill Ted Kennedy's seat after his death, he won campaigning heavily against Obamacare; but two years later, he lost to Elizabeth Warren by almost eight points.

"Obamacare is proving to be an issue that is turning safe Democrats into vulnerable Democrats," said Will Ritter, a Massachusetts GOP consultant and former Brown staffer. "Scott Brown has run against Obamacare before successfully, he has got deep ties to New Hampshire … he knows how to raise money, knows how to campaign hard, and he's likeable."

If Brown does get in, the race will instantly skyrocket to the one of the most competitive and highly watched in the country. In a statement Matt Canter, deputy executive director for the Democratic Senatorial Campaign Committee, said, "If Scott Brown decides to run, he'll have a lot more to explain than just his driver's license."

"Brown was named Wall Street's favorite senator by Forbes magazine because he did their bidding in the Senate," Canter said. "Since he was rejected by voters, Brown has been getting rich lobbying on Wall Street's behalf. Massachusetts voters realized that Scott Brown was only out for himself and if he runs, New Hampshire voters will come to the same conclusion. Only question in my mind is, does he finally go away then, or is that when he thinks he should run for president."

The Democratic National Committee had a similar response to the possibility, with spokesperson Michael Czin noting Brown graced the front page of the Des Moines Register just last month "talking about running for president, so I think that's what he really wants."

Brown may be spending time on the ground in New Hampshire hitting up both large and small events, but Republican strategist Jamie Burnett said he has "seen no evidence that Scott Brown is making calls to key activists or donors, no evidence that he is trying to organize in the state even quietly."

"It's hard to guess what his intentions are," said Burnett, "but there's an opportunity because we have not recruited a strong candidate for U.S. Senate in New Hampshire yet."

Burnett added that up until now his visits to Iowa, as well as New Hampshire, made it unclear if he was "running for Senate, running for president, or growing his brand."

Richard Killion, another longtime GOP strategist in the state, agreed that Brown has been "consistent" in coming to the state, but said "his intentions are completely unknown and if anyone says they know, they are just guessing. No one knows."

This story has been updated to correct the day of Scott Brown's event in Londonderry.